An Active Matrix Organic Light Emitting Display (AMOLED) has advantages such as self-illumination, low power consumption, fast response speed, high contrast and wide angle of view.
In the process of the manufacturing an AMOLED display panel, a portion with gaps of a mask is used to perform evaporation on red (R) pixels, green (G) pixels, and blue (B) pixels, respectively; further, during the evaporation process, a non-evaporation region (i.e., a region in which the evaporation process is not to be performed) is shielded by a portion without gap of the mask. FIG. 1 is a schematic diagram showing the structure of a mask in the prior art. As shown in FIG. 1, a mask 10 includes an active region 11 and a transition region 12. The active region 11, which functions as an evaporation region, corresponds to a display area of the AMOLED display panel; and the transition region 12, which functions as a non-evaporation region, corresponds to a transition area between the AMOLED display panels. The active region 11 further includes gaps 111 formed by etching and used for the evaporation, while the transition region 12 is not etched.
Before the evaporation, a tension force is applied to the mask by a stretching device to stretch the mask with the tension force, and then the flattened mask is welded on a metal frame to maintain a flat state of the whole mask. Because of the structure design of the mask in the prior art, in which the active region 11 includes the gaps 111 formed by etching but the transition region 12 is not etched, the forces applied to the active region 11 and the transition region 12 are distributed unevenly when the mask is applied by the tension force, thus worsening the flatness of the mask. During the evaporation process, the mask with the worsened flatness would cause color mixture in the AMOLED display panel, thereby decreasing the yield of the display panel.